FALL RIVER — Electrical wiring in the attic of a 4th Street home ignited a mattress and caused a fire that displaced two residents and their dog Sunday evening, according to a fire official.

Firefighters received multiple 911 calls about 7:50 p.m. from residents of the 591 4th St. multi-family home who managed to evacuate, according to Fall River Captain and investigator Neil Furtado.

Officials saw smoke on arrival and encountered flames when they entered the attic of the three-story structure, Furtado said.

Firefighters put down the flames in just about 10 minutes, at which time officials began to probe the apparent cause of the blaze.

According to Furtado, residents told a fire investigator on scene they had been smelling smoke inside the residence for “quite a bit of time.”

“This was actually a long burn. It was a smouldering fire over a long time,” Furtado said.

An old mattress had been discarded in the attic and was placed atop electrical wiring, according to the investigator.

The electrical system was powering a number of appliances, including an air-conditioning unit, that were drawing more electricity than the circuit was designed to handle, causing the circuit to overload, according to Furtado.

One firefighter suffered a shoulder injury while responding to the blaze and was treated Monday morning, Furtado said.

A preliminary estimate pegs the damage to the home at about $20,000 to $25,000.

Two people and a dog who lived in the third-floor unit of the residence were displaced from their apartment, Furtado said. Occupants of the first- and second-floor units were able to return to their homes.

No residents were injured, according to the fire department.

Furtado said the fire serves as a reminder to be mindful of how much electricity a home’s appliances are drawing, particularly with the addition of air-conditioning units in the hot summer months.

Residents should not simply reset their circuit breakers if they trip, indicating too much electricity is flowing through it.

“You've got to be cognizant of the breakers. If it trips, it's tripping for a reason,” Furtado said. “It would be like your engine light coming on and you putting a piece of tape over it and ignoring. It doesn’t make sense.”

Email Amanda Burke at aburke@heraldnews.com.